﻿// 1026 程序运行时间.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//

#include <iostream>
#include<cstdio>
using namespace std;

int main()
{
    long a, b;
    cin >> a >> b;
    int seconds = double(b - a) / 100 + 0.5;
    int hours = seconds / 3600;
    seconds = seconds % 3600;
    int minutes = seconds / 60;
    seconds = seconds % 60;
    printf("%02d:%02d:%02d", hours, minutes, seconds);
    return 0;
}